Cookbook

Sample app: Fieldbook

A small but real app on one Rust core: field notes with photos, on the web, iOS and Android.

What it is#

Fieldbook is a small but real app: field notes with photos, for a team that works where there is no signal. One Rust core, three apps (web, iOS, Android) that use only the public API, and a test suite that runs the core with no device. The cookbook's recipes, in one product.

What it demonstrates#

Feature	In the core
Sign-in with a team code, tokens in the secure store, one re-auth on a 401	`auth.rs`
A note is on the device before the screen shows it, and is sent when there is a network, even after a kill	`notes.rs`: `Kv`, an idempotent `push_note`
Search, tag chips, pinned first, newest first	a keyed list, a `DerivedList` and a `Computed`
Photos kept in the app's files and uploaded in the background	`Fs` and the queue
An update that renames a field and adds three, without losing data	`#[undra(default)]`, `#[undra::migrate]`
Who else is in the notebook	`presence.rs`: a reconnecting WebSocket (feature `presence`)
State kept across a rebuild under `undra dev`	every store has a `restore` function, tested

Run it#

Show the commands

shell

cd examples/fieldbook/web && npm install && npm run dev   # the web app, with an in-page demo server (team code: fieldbook)
node examples/fieldbook/server/server.mjs                    # a backend for the iOS and Android apps
cargo test -p fieldbook-core                                  # the core, against the fakes
cd examples/fieldbook/web && npm test                          # the bindings over the real wasm core

Tick offline in the web app, write two notes, reload, untick it: the notes were on the device the whole time, and the core sends them when the network returns.

How far it goes#

The web, iOS and Android apps build in CI (vite build, xcodebuild, assembleDebug); the screens are small on purpose.
Notes are stored in Kv. The Db port (SQLite) is the next step for a notebook that grows; it is an opt-in port.
SwiftUI previews and the web stories run the real core on the testing kit's fakes, and so do the web tests, with a manual clock. Android's Compose previews are not in the sample: they play a recording, and none was made.

Source: examples/fieldbook, with a README that says how to run each platform. The cookbook has the recipes it is made of.

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